Ch31-IntroVirology & phage-with highlights Flashcards by G G

Viruses

simple organization
• DNA or RNA genome
• unable to reproduce outside of
living cells
• obligate intracellular parasites

How well did you know this?

Not at all

Perfectly

Pandora Virus is

Big ass MF virus. 1000nm.

How well did you know this?

Not at all

Perfectly

Multicomponent viruses genomes are segmented and the

segments are distributed into separate ……………

Mosquito Virus:

Multiple distinct particles required for infection

How well did you know this?

Not at all

Perfectly

Cultivation of viruses requires inoculation of

living host cell

suitable animals
• embryonated eggs
• tissue (cell) cultures
– monolayers of animal cells
– plaques
• localized area of cellular destruction and lysis

How well did you know this?

Not at all

Perfectly

cytopathic effects (CPEs)

microscopic or macroscopic degenerative changes or

abnormalities in host cells and tissues

How well did you know this?

Not at all

Perfectly

Naked Capsid Virus

RNA/DNA + Structural Protien + Enzymes nucleic acid binding proteins=nucleocapsid=Naked capsid

How well did you know this?

Not at all

Perfectly

Enveloped protien =

Nucleocapsid + Glyco proteins and membrane = Enveloped Virus.

How well did you know this?

Not at all

Perfectly

Herpes Shape

Isosahedral capsid HSV-1

How well did you know this?

Not at all

Perfectly

Capsomers

Capsid proteins

How well did you know this?

Not at all

Perfectly

Bacteriophage T4 Capsid

Isosahedral + Tail

Contains DSDNA

How well did you know this?

Not at all

Perfectly

Filamentous Virus

Helical Symetry

Protein arranged in monomeric units

How well did you know this?

Not at all

Perfectly

Enveloped Virus’s’s have?

Glycoprotien spikes attached to liped bilayer

How well did you know this?

Not at all

Perfectly

Example of asymtrical virus?

Vaccina Pox
Surrounded by outer membrane and contains core enveloped which envelopes DSDNA which is stabilized by hair pin loop at each end.

How well did you know this?

Not at all

Perfectly

Single Stranded Positive Sense Fall under what Groupd of Virus.

RNA/Noneveloped

How well did you know this?

Not at all

Perfectly

Single stranded Positive sense RNA is grouped by?

Uneveloped RNA Virus and Enveloped

How well did you know this?

Not at all

Perfectly

What to types Virus groups are unique to enveloped RNA type fools

Retro Virus and Negative sense single stranded

In terms of DNA of virus what nucleic acid characteristic are shared between enveloped and non enveloped types.

DS Linear DNA and DS circular DNA

Single Stranded linear DNA is unique to what type of virus (enveloped v. nonenveloped)

Nonenveloped

Virus Replication Steps

adsorption
–penetration and uncoating
–synthesis of viral proteins and nucleic acids
–assembly of virions
–release

Adsorption of Virions
• viral surface ____________ and/or _________
mediate attachment to specific host
____________

Adsorption of Virions
• viral surface proteins and/or enzymes
mediate attachment to specific host
receptors

Penetration and Uncoating

• three mechanisms

-injection of nucleic acid
– fusion of envelope with host membrane
– endocytosis

Assembly of Virus Capsids

capsid proteins
– encoded by late genes
• assembly of naked viruses
– empty procapsids formed then nucleic acid
inserted
• assembly of enveloped viruses
– in most cases, similar to assembly of naked
viruses
• site of morphogenesis varies

Virion Release

• naked viruses

usually by lysis of host cell

Virion Release

Enveloped Virus

formation of envelope and release usually
occur concurrently
• virus-encoded proteins incorporated into host
membrane
• nucleocapsid buds outward and is surrounded
by modified host membrane

What are some examples of phage receptors?

ToLC, OMPF, LPS and Flagella proteins

Phage C1 Viral genome that provide host traits

Botulnum Toxin (c1)

Beta Phage (corynebacterium diphtheria)

Dipotheria Toxin (tox) (corynebacterium diphtheria)

Human endogenous Retro Virus | HERV-W

Syncytin (retroviral ENV protien) : placental Fusion.

HERV-E

Apolipoprotein C1 ( facks with liver function)

Bacteriophage cylcle slow release

Bacteriopahge exit cell without lysis. | Host cell reproduces more slowly because the phage is using the host cells resources (AH).

Bacterial Defense against Phages

Genetic resistance – mutations in bacterial genes (e.g. receptor) Restriction endonucleases – enzymes that cut invading DNA CRISPR – a bacterial immune system

CRISPR – a bacterial immune system

A piece of phage DNA gets copied into host genome (crispr). Upon reinfection, the crispr is translated and combines with Cas complex which then recognizes and cleaves phage DNA...more or less.

Phage therapy being explored as a potential

antibiotic treatment